FAIRFIELD, Calif. (AP) — A fire apparently sparked along a freeway spread to a grassy hillside, jumped into trees and then burned several homes in a crowded Northern California neighborhood.

Public Information Officer Gale Spears says two houses were completely destroyed and three others were damaged in the city of Fairfield, about 40 miles northeast of San Francisco. The homes were on Marigold Drive near Interstate 80.

Spears says fire crews worked quickly to protect dozens of threatened structures including houses and a nearby apartment complex. At least 50 homes were evacuated.

Several cars in a parking lot along I-80 also went up in flames. Thick black smoke briefly shut two lanes of the interstate.

The cause of the blaze is unknown. Spears says investigators believe it started along the freeway.